Archive for Bees

WHAT’S ALL THE BUZZ ABOUT NOBEL PRIZE SEASON?

Posted in Ants, bees, wasps with tags , , , on October 10, 2010 by Dr. Art Evans

By Arthur V. Evans

There have been plenty of reports in the news lately regarding the 2010 Nobel Prizes awarded for cultural and scientific endeavors. The prizes were established in 1895 in the will of the Swedish chemist Alfred Nobel, whose fortune was built on, among other things, the invention of dynamite. First awarded in 1901, the prizes are given annually in recognition of outstanding achievement in the fields of chemistry, literature, medicine, physiology or medicine, and physics. The best known and often controversial prize is the Nobel Peace Prize.

This is a good time to recall that nearly 40 years ago Austrian Karl von Frisch (1886-1982) received the Nobel Prize  in Physiology or Medicine in 1973, along with Nikolaas Tinbergen and Konrad Lorenz, for his pioneering work on communication between insects by studying the sensory perceptions of honey bees that led to the deciphering of their waggle dance in 1946. You can download a copy of von Frisch’s Nobel Lecture here.

Although sometimes claimed by entomologists as one of their own, Von Frisch was actually an ethologist, a zoologist that examines animal behavior relative to their environment. His studies with honey bees (Apis mellifera) produced several revelations. For example, von Frisch discovered that foraging bees were able to discriminate among different species by their scent and that individuals bees consistently forage among the same species of flower. He also learned that, in spite of a great sense of smell, the sense of taste is not particularly well-developed in bees.

He also established that bees can distinguish the colors of  blue, violet, white, and yellow, but that black and red were colorless and therefore indistinguishable to them. Under ultraviolet light, the pigments that make up these colors appear as multicolored patterns called nectar guides.

Von Frisch determined that bees orient themselves and can tell time of day primarily by their relative position to the sun. On overcast days or inside their hives, bees can still do all this by using the polarized light pattern of even a small patch of blue sky, or by relying the Earth’s magnetic field when moving about inside the hive, respectively.

Using all the tools at their disposal, Karl von Frisch proposed that not only do bees have the ability to gather orientation and temporal information from the sun’s daily movement across the sky, they can also relate this information to the current position of the sun from the dark recesses of the hive. This allows foraging bees returning from the field to provide up-to-date information on the direction and distance of nectar sources to their hive mates without having to go back outside to reorient themselves. This information is relayed by performing two basic kinds of “dances.” The information conveyed in these dances is received and interpreted on the vertical surface of the comb and put into practice on a horizontal landscape.

The round dance communicates information about nearby nectar sources about 50-100 meters from the hive. Whirling about in a tight circle, the dancing bee completes two circuits one way, then abruptly turns the other for two more circuits. Delivered on a thickly populated section of comb, bees in the immediate vicinity of the dancing bee struggle to keep their antennae in contact with the dancer’s abdomen. Soon the dancing bee’s wake is filled with bees all fervently trying to keep in step. Direction is not conveyed during the dance, but the type of flowers is transmitted through the dancing bee’s odor.

The waggle dance presents information on distant pollen and nectar sources. The dancing bee moves a specific distance in a straight line on the comb, turns and walks a half circle, then retraces the straight line and waggles its abdomen. Turning in the other direction, the bee completes a figure-8 pattern and waggles along the straight line again. The direction of the straight line relative to the vertical plane of the comb reveals the precise direction of food source relative to the position of the sun. The intensity of the dance, as measured by the number of times the waggle dance is performed informs the other bees as to distance of the food source. Bees receive and reinforce this information by copying the dance and by sensing the odors of dancing bee. Fully informed by the waggle dance, the newly recruited bees leave the hive and locate the food source regardless of intervening physical barriers, natural or man-made.

My first exposure to von Frisch and his groundbreaking work with honey bees was through the 1964 Life magazine article about his life and research at the tender young age of seven. Later in 1966, I saw him in one of the very first National Geographic television specials, The Hidden World of Insects (another milestone in this entomologist’s fascination with insects). I clearly remember being fascinated by his painstaking experiments with experimental feeding stations set among open grassy habitats and stocked with petri dishes of different colors and filled with various sugar solutions.

Karl von Frisch also studied the pheromones produced by queen honey bees and the role they had in maintaining the social order of the colony. Although he published all of his is original findings in German, von Frisch did produce some popular works in English. Two of these titles have long been in my library. Both works are fascinating to read. Animal Architecture covers both vertebrates and invertebrates, including some wonderfully illustrated information on the structures built by arthropods.

Scientists have long been skeptical or flat-out rejected von Frisch’s work with honey bees and his results suggesting that these industrious insects had a language all their own. Recent studies suggest that the importance of the bee’s dance may not be as great as once thought and that most of the bees that witness the dance get it all wrong, if they don’t just ignore it altogether. Only a few workers that “get” the information actually find the food source.

Other scientists are not ready just yet to discount the importance of dancing bees to the overall success of the hive. Both camps agree that most of the research thus far has focused on the message delivered by dancing bees and that there is still much to be learned how this information is perceived by other members of the hive.

WEB SOURCES:

2009. The bees’ knees-The facts. New Internationalist Magazine. http://www.newint.org/features/2009/09/01/facts-about-bees/ (accessed 10 October 2010)

2010. Karl von Frisch. Wikipedia. The Free Encyclopedia.  http://en.wikipedia.org/wiki/Karl_von_Frisch (accessed 10 October 2010)

PRINT SOURCES

von Frisch, K. 1953. The dancing bees. An account of the life and senses of the honey bee. New York: Harcourt, Brace & World Inc. 182 p.

von Frisch, K. 1974. Animal architecture. New York: Harcourt, Brace, Jovanovich. 306 p.

Williams, C. 2009. Show me the honey. New Scientist 203 (2726): 40-41.

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